In late 2018, a Miami Herald report on a controversial non-prosecution agreement with billionaire Jeffrey Epstein, a serial child molestor,[8] which had been approved by Acosta a decade earlier while he was serving as US Attorney for Southern District of Florida, became a focus of Congressional concern and led to calls for an independent investigation and for Acosta's resignation from the Trump Administration.

On December 31, 2013, Acosta became the new chairman of U.S. Century Bank,[14] the largest domestically owned Hispanic community bank in Florida and one of the 15 largest Hispanic community banks in the nation. He spearheaded the effort to establish the J.M. degree in banking compliance, BSA and anti-money-laundering at FIU Law. Acosta was a member of the Board of Trustees of Gulliver Schools, where he served a past term as board chairman.[15]

Then, he became Assistant Attorney General for the Civil Rights Division on August 22, 2003,[18] where he was known for increasing federal prosecutions against human trafficking.[19] He authorized federal intervention in an Oklahoma religious liberties case to help assure the right to wear hijab in public school, [20] and worked with Mississippi authorities to reopen investigation of the 1955 death of Emmett Till, a 14-year-old black youth whose abduction and killing helped spark the civil rights movement.[21][22]

While leading the Civil Rights division, Acosta allowed his predecessor, Bradley Schlozman, to continue to make decisions on hiring.[23] A report by the Inspector General and the Office of Professional Responsibility later found that Schlozman illegally gave preferential treatment to conservatives and made false statements to the Senate Judiciary Committee. Those findings were relayed to the office of the United States Attorney for the District of Columbia,[16] but Schlozman was not prosecuted.[23] While it put the primary responsibility on Schlozman, the report also concluded that Acosta "did not sufficiently supervise Schlozman" and that "in light of indications [he and Principal Deputy Assistant Attorney General Sheldon Bradshaw] had about Schlozman's conduct and judgment, they failed to ensure that Schlozman's hiring and personnel decisions were based on proper considerations."[16][23]

The District also targeted white collar crime, prosecuting several bank-related cases, including one against Swiss bank UBS. The case resulted in UBS paying $780 million in fines, and for the first time in history, the bank provided the United States with the names of individuals who were using secret Swiss bank accounts to avoid U.S. taxes.[25]

Other notable cases during his tenure include the corruption prosecution of Palm Beach County Commission Chairman Tony Masilotti, Palm Beach County Commissioner Warren Newell, Palm Beach County Commissioner Mary McCarty,[26] and Broward SheriffKen Jenne; the conviction of Cali Cartel founders Miguel and Gilberto Rodríguez Orejuela, for the importation of 200,000 kilos of cocaine, which resulted in a $2.1 billion forfeiture; and the white-collar crime prosecutions of executives connected to Hamilton Bank.[27]

Acosta also emphasized health-care fraud prosecutions. Under Acosta's leadership the District prosecuted more than 700 individuals, responsible for a total of more than $2 billion in Medicare fraud.[28]

In 2007-2008, while serving as the U.S. attorney for Southern Florida, Acosta approved a controversial non-prosecution agreement [29] (Jeffrey Epstein case).

In late 2018, as Acosta's name was being circulated as a possible successor to Trump Administration Attorney General Jeff Sessions, the Epstein case became a focus of Congressional concern. This followed publication by the Miami Herald of a detailed report critical of Acosta's work on the case,[30] in which Jeffrey Epstein, a multimillionaire hedge fund manager with influential connections (including Bill Clinton, Donald Trump, Prince Andrew and many others[8]), was said to have recruited minor girls from Palm Beach County middle schools and high schools for lewd massages and other paid sexual activities at his Florida mansion. Acosta approved a federal non-prosecution agreement[29] under which Epstein, along with four co-conspirators and any unnamed “potential co-conspirators”, were granted immunity from all federal criminal charges. To avoid federal prosecution, Epstein agreed to plead guilty to two state prostitution charges, register as a sex offender, and pay restitution to three dozen victims identified by the FBI. The state court sentenced Epstein to 18 months’ incarceration, and he served 13 months, followed by a year of probation. His sentence was served in a private wing of the Palm Beach County Stockade, with work release to his office allowed for up to 12 hours a day six days a week.[31] While on probation, he was allowed numerous trips on his corporate jet to his homes in Manhattan and the U.S. Virgin Islands.[32] In a 2011 public letter about the case, Acosta himself seemed to express dissatisfaction with the terms of Epstein's incarceration, stating: "Epstein appears to have received highly unusual treatment while in jail. Although the terms of confinement in a state prison are a matter appropriately left to the State of Florida, and not federal authorities, without doubt, the treatment that he received while in state custody undermined the purpose of a jail sentence." [33] The immunity agreement and Epstein's lenient treatment while incarcerated were the subject of ongoing controversy, with the Miami Herald saying in 2018 that Acosta gave Epstein "the deal of a lifetime".[34]

Subsequent to the federal non-prosecution agreement, additional information came to light indicating that Epstein's activities may have been significantly more extensive—perhaps affecting hundreds of minors, believed to have been recruited from the US and overseas to attend sex parties at Epstein homes in Florida, New York, New Mexico, and the US Virgin Islands, and aboard his private jet—it is alleged that girls as young as 13 were expected to perform sexual favors for Epstein and his guests. Although there have been books[35][36]and a number of news reports related to these additional alleged activities, criminal charges against Epstein have not been filed in jurisdictions other than Florida. The case was scheduled to be examined in court for the first time in December 2018 as part of a civil lawsuit against Epstein, but that suit was settled before witnesses gave testimony.[37][38]

Acosta's own account of his office's role in the Epstein case was published in 2011.[39] It was also covered in his Senate testimony for confirmation as Trump Administration Secretary of Labor.[40][41]

Following publication of the November 28, 2018 Miami Herald article about the Epstein case,[30] Acosta was removed from consideration for US Attorney General, members of Congress submitted a formal request to the US Department of Justice for review of Acosta's role in the Epstein deal[42], and several editorials called for Acosta's resignation or termination from his then-current position as US Labor Secretary. [43][44]

David Markus, a Florida defense attorney familiar with Acosta's work as US Attorney for Southern District of Florida offered a contrarian view, stating: "[T]here are many — including the New York Times, Miami Herald, and others — who are calling for Congress to investigate Acosta and force him out, equating Acosta’s approval of the deal to Epstein’s actions. Although it is fair to have an honest disagreement about the Epstein plea agreement, the attacks on Acosta are not justified....At the time this case was being investigated, there were serious questions about whether Epstein’s crimes had the required federal nexus. These were traditional state court crimes with local victims, which the federal government decided should be prosecuted by the state system....In addition, there were legitimate concerns about how a trial would have turned out. These trials are difficult.... Here, prosecutors have said that many of the victims either refused to testify or were going to say things that helped Epstein." [45]

Former federal prosecutor, Jeffrey Sloman, echoed this view, writing: “Our priorities were to make sure Epstein could not hurt anyone else and to compensate Epstein’s victims without retraumatizing them. Our team worked diligently to build a federal case against Epstein. Throughout the investigation, we took care to be respectful of the pain Epstein’s victims had endured. As we continued, however, it became clear that most of Epstein’s victims were terrified to cooperate against him. Some hired lawyers to avoid appearing before a grand jury. One of the key witnesses moved to Australia and refused to return calls from us. We also researched and discussed significant legal impediments to prosecuting [in federal court] what was, at heart, a local sex abuse case. Given the obstacles we faced in fashioning a robust federal prosecution, we decided to negotiate a resolution. ….You can disagree with the result we reached, but our whole team — from Alex [Acosta] on down the chain of command — always acted with integrity and in good faith.” [46]

In December 2018, a Labor Department spokesperson replied to questions about renewed interest in the Epstein case as follows: "For more than a decade, this prosecution has been reviewed in great detail by newspaper articles, television reports, books, and Congressional testimony, and has been defended by the Department of Justice in litigation across three administrations and several attorneys general. If the Department of Justice’s Office of the Inspector General chooses to review this matter, Secretary Acosta welcomes the opportunity to participate."[47]

On February 21, 2019, a ruling in federal court on a related matter returned Acosta's role in the Epstein case to the headlines.[51][52][53][54] A key criticism of the Epstein case was that the federal deal with Epstein had been kept secret until after it was finalized, a practice that had been common prior to passage of the Crime Victims' Rights Act of 2004 (CVRA), which requires notifying victims of the progress of federal criminal cases. The CVRA was new and relatively untested at the time of the Epstein non-prosecution agreement. In 2008, two of Epstein's victims filed a lawsuit in federal court aiming to vacate the federal non-prosecution agreement on the grounds that it violated the CVRA.[34] For more than a decade, the US Attorney's office denied that it acted in violation of victims' rights laws and argued that the CVRA did not apply in the Epstein case.[55] The government's contention that the CVRA did not apply was based on questions of timing (whether or not CVRA applied prior to filing of federal charges) and jurisdiction (whether the case should be considered a federal case or a state case under the CVRA). The court rejected those arguments in the February 21, 2019 ruling, finding that the CVRA did apply and that victims should have been notified of the Epstein non-prosecution agreement in advance of its signing, to afford them the opportunity to influence its terms. Because the CVRA does not provide for specific penalties in cases where the government fails to meet its notification requirements, the judge gave the parties fifteen days to present the court with possible remedies. At the conclusion of his ruling, Kenneth Marra, the federal judge in the case, noted that he was “not ruling that the decision not to prosecute was improper,” but was “simply ruling that, under the facts of this case, there was a violation of the victims rights [for reasonable, accurate, and timely notice] under the CVRA .”[56]

On April 27, 2017, Acosta was confirmed as Secretary of Labor by the U.S. Senate in a 60–38 vote. He received the votes of 8 Democratic Senators and all Republican Senators except Senator Pat Toomey (R-PA), who did not participate in the vote.[64]

Acosta has twice been named one of the nation's 50 most influential Hispanics by Hispanic Business Magazine. He serves on the Florida Innocence Commission,[65] on the Florida Supreme Court's Commission on Professionalism,[66] and on the Commission for Hispanic Rights and Responsibilities.[67]